Chapter 35 - The Coral Reef Province of Brazil

Abstract

On the tropical coast of Brazil, coral reefs are prominent marine ecosystems, forming the largest and richest area of reefs in the southwestern Atlantic Ocean. These reefs are characterized by an unusual growth form of mushroom-shaped pinnacles, formed by a low diversity coral fauna rich in endemic species. The inshore reefs thrive in an environment influenced by a continentally derived intense siliciclastic sediment influx, whereas offshore reefs develop in the carbonate dominated middle and outer continental shelves. The inshore reefs are experiencing increasing degradation due to both natural processes (sea-level oscillations, ENSO events) and anthropogenic impacts, such as an accelerated coastal development, reef nutrification, marine pollution, tourism pressure, overexploitation of reef resources, and overfishing. A lowering of sea level that occurred after 5000 years BP, along the coast of Brazil, affected most coastal habitats, mobilizing the western continent-derived siliciclastic sediment toward the eastern reefs and associated habitats, exposing them to a heavy sedimentation. Coral bleaching events occur in the reefs of Brazil during El-Niño occurrences. Accelerated deforestation of coastal zones for urban development has been causing high influx of sediment to the reefs, mangrove forests, and seagrasses. Tourism pressure is already impacting the most visited areas including the yet still few number of marine protected areas (MPAs), and the number of divers per year is already high enough to be deleterious to the reefs. Extraction of coral fauna for the aquarium trade, overfishing and fishing with explosives in both the artisanal and commercial fisheries, and use of chemicals for indiscriminate catching of aquarium fishes are responsible for the mortality of some components of the reef biota. Effective protection of Brazilian reefs is still minimal, and for certain areas, was virtually nonexistent until the beginning of this century, when an initiative of the Directorate of Protected Areas of the Brazilian Government developed a project for the conservation of coral reefs, expanding its effort to map those found in existing Conservation Units, distributed along the entire coast of Brazil and including nearly all of the country’s oceanic islands.